Could Peanut Butter Be the Key to Early Alzheimer's Detection?

Tuesday, October 22nd, 2013 by Angela Stringfellow

In a new study by a graduate student at McKnight Brain Institute Center for Smell and Taste and the University of Florida, researchers find that peanut butter could hold valuable clues to detecting Alzheimer's disease, according to a report on the findings at Futurity.org. Graduate student Jennifer Stamps came up with the idea when working with Kenneth Heilman, a professor of neurology at the University of Florida.

Sense of smell linked to an important part of the brain

It's not that peanut butter is some magical substance, however. The study is based on the concept that the sense of smell is often affected in the early stages of Alzheimer's disease. That's because the sense of smell is linked to the first cranial nerve -- one of the first areas of the brain to be impacted by cognitive decline. Peanut butter serves as a good gauge of the strength of the sense of smell, since it's a "pure odorant" and is only detected by the olfactory nerve.

The front portion of the temporal lobe is the first area of the brain to degenerate in Alzheimer's patients, and it's the area of the brain that has evolved from the smell system. It's also a portion of the brain involved in the creation of new memories -- which is why many Alzheimer's patients in the early stages of the disease first begin to show symptoms of short-term memory loss.

Left nostril vs. right nostril performance is a key indicator

The simple, inexpensive study is published in the Journal of Neurological Sciences. Researchers use a ruler and 14 grams of peanut butter (equal to about one tablespoon) to gauge participant's ability to smell. Participants close their eyes and hold one nostril closed, while researchers hold the ruler next to the nose. The peanut butter is slowly moved up, inch by inch, until participants are able to detect the smell. The distance at which participants were able to detect the smell of peanut butter was recorded and the procedure repeated -- after a 90-second delay -- with the other nostril.

Findings indicate a significant difference between the right and left nostril among patients who were later determined to be in the early stages of Alzheimer's disease. In Alzheimer's-diagnosed participants, the left nostril was significantly impaired compared to the right -- not detecting the smell of peanut butter until an average of 10 centimeters closer to the nose than when the process was conducted with the right nostril.

The findings are not consistent across participants with different types of dementia, however. In those participants, there was either no difference in the detection distance or the right nostril was impaired compared to the left.

Is peanut butter a good diagnostic tool?

Overall, 24 participants were tested who have mild cognitive impairment. Ten of those participants showed a left nostril impairment, while the remaining 14 did not. While researchers say future studies are needed to determine the potential implications, they do say that this simple test can be used to confirm diagnosis in clinics and healthcare settings where more expensive diagnostic tests aren't readily available. Many settings lack the personnel or equipment to perform advanced testing -- not to mention, these sophisticated diagnostic tests can be quite expensive. The peanut butter test can be used as an affordable alternative to confirm a suspected diagnosis, allowing providers to prescribe more adequate treatment plans in the early stages of the disease.

Would you trust the peanut butter test? It might seem like an elementary science experiment, but sometimes the greatest discoveries are the most obvious things right under our noses. (Pun intended.)